engleski

A Portable Planar Coil Array for Frequency-Domain Inductive Sensing of Metallic Objects

In order to accurately detect, characterize, classify or locate subsurface metallic objects using portable, electromagnetic induction (EMI) sensors, EMI data of high spatial diversity are needed. In a scanning sensor set-up, such data can be provided by planar coil arrays. Unfortunately, these are often difficult to implement, especially in case of frequency-domain (FD) EMI sensors where each receive coil needs to be inductively balanced with respect to the transmitter. In this paper, we propose a design of a novel planar coil array featuring single transmit and seven receive coils arranged in a compact search head suitable for application in handheld FD EMI sensors. We explain the evolution of our coil array design and analyze its capability to induce directional EMI responses from dipole-like targets in a context of inversion-based inductive metal characterization. We illustrate its benefits by comparing its inversion performance to two single-receiver coil designs commonly found in conventional FD metal detectors. Finally, we provide an insight into the array’s practical implementation.

EMI sensor, coil array, induction balance, metal detection, metal characterization, induced dipole model

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